ASK FOR INFORMATION RETRIEVAL: PART I. BACKGROUND AND THEORY

We report the results of a British Library Research and Development Department funded design study for an interactive information retrieval system which will determine structural representations of the anomalous states of knowledge (ASKs) underlying information needs, and attempt to resolve the anomalies through a variety of retrieval strategies performed on a database of documents represented in compatible structural formats. Part I discusses the background to the project and the theory underlying it, Part II (next issue) presents our methods, results and conclusions. Basic premises of the project were: that information needs are not in principle precisely specifiable; that it is possible to elicit problem statements from information system users from which representations of the ASK underlying the need can be derived; that there are classes of ASKs; and, that all elements of information retrieval systems ought to be based on the user\u27s ASK. We have developed a relatively freeform interview technique for eliciting problem statements, and a statistical word co-occurrence analysis for deriving network representations of the problem statements and abstracts. Structural characteristics of the representations have been used to determine classes of ASKs, and both ASK and information structures have been evaluated by, respectively, users and authors. Some results are: that interviewing appears to be a satisfactory technique for eliciting problem statements from which ASKs can be determined; that the statistical analysis produces structures which are generally appropriate both for documents and problem statements; that ASKs thus represented can be usefully classified according to their structural characteristics; and, that of thirty-five subjects, only two had ASKs for which traditional \u27best match\u27 retrieval would be intuitively appropriate. The results of the design study indicate that at least some of our premises are reasonable, and that an ASK-based information retrieval system is at least feasible

ASK FOR INFORMATION RETRIEVAL: PART II. RESULTS OF A DESIGN STUDY

In \u27ASK for Information Retrieval: Part P1, we discussed the theory and background to a design study for an information retrieval (IR) system based on the attempt to represent the anomalous states of knowledge (ASKs) underlying information needs. In Part 11, we report the methods and results of the design study, and our conclusions

Celebrating Stephen Robertson's retirement

Stephen Robertson retired from the Microsoft Research Lab in Cambridge during the summer of 2013 after a long career as one of the most influential, well-liked and eminent researchers in Information Retrieval throughout the world

Design Principles of 5G NR RoF-Based Fiber-Wireless Access Network

For today, much attention in the upcoming 5G New Radio (NR) mobile networks is paid to radically expanding the available spectral bands up to millimeter wavelengths (MMW). Following this tendency, currently, the local telecommunication commissions of various countries are proposing and harmonizing the plans of frequency allocation in MMW band, which will be reviewed this year at the World Radio Conference (WRC-2019). Another milestone of great importance is the development of access networks. Here, well-known radio-over-fiber (RoF) technology is considered as the most promising approach, which is implemented based on fiber-wireless (FiWi) architecture. Elaborating the direction, in this chapter we review the worldwide progress of RoF-architected 5G NR access networks and highlight our last simulation results on design and optimization of millimeter-photonic-based FiWi interface. All schemes are modeled using VPIphotonics Design Suite software tool. In the result of simulation experiments, optimal design principles of optical distribution network (ODN), fiber-wireless interface (FWI), and fiber-wireless fronthaul network (FWFN) as a whole have been proposed, described, and validated

The chemistry of stabilised sulphonium ylides

The review is devoted to the chemistry of stabilised sulphonium ylides, i. e. ylides with substituents at the carbanionic carbon atom capable of delocalising its negative charge. The physical properties of compounds of this class are examined and the methods of synthesis of stabilised sulphonium ylides, their rearrangements, and their reactions with electrophiles and nucleophiles are described. The structures and reactivities of the complexes of stabilised sulphonium ylides with transition metals and their organometallic derivatives are considered. The practical applications of the stabilised sulphonium ylides are indicated. © 1981 IOP Publishing Ltd

Design of Reconfigurable Multiple-Beam Array Feed Network Based on Millimeter-Wave Photonics Beamformers

In this chapter, elaborating the direction of designing photonics-based beamforming networks (BFN) for millimeter-wave (mmWave) antenna arrays, we review the worldwide progress referred to designing multiple-beam photonics BFN and highlight our last simulation results on design and optimization of millimeter-photonics-based matrix beamformers. In particular, we review the specialties of mmWave photonics technique in 5G mobile networks of Radio-over-Fiber (RoF) technology based on fiber-wireless architecture. In addition, the theoretical background of array antenna multiple-beam steering using ideal models of matrix-based phase shifters and time delay lines is presented including a general analysis of radiation pattern sensitivity to compare updated photonics beamforming networks produced on phase shifter or true-time delay approach. The principles and ways to optimized photonics BFN design are discussed based on the study of photonics BFN scheme including integrated 8×8 optical Butler matrix (OBM). All schemes are modeled using VPIphotonics Design Suite and MATLAB software tools. In the result of simulation experiments, the outcome is obtained that both the integrated optical Butler matrix itself and the BFN based on it possess an acceptable quality of beams formation in a particular 5G pico-cell

Smoothed Analysis of Tensor Decompositions

Low rank tensor decompositions are a powerful tool for learning generative models, and uniqueness results give them a significant advantage over matrix decomposition methods. However, tensors pose significant algorithmic challenges and tensors analogs of much of the matrix algebra toolkit are unlikely to exist because of hardness results. Efficient decomposition in the overcomplete case (where rank exceeds dimension) is particularly challenging. We introduce a smoothed analysis model for studying these questions and develop an efficient algorithm for tensor decomposition in the highly overcomplete case (rank polynomial in the dimension). In this setting, we show that our algorithm is robust to inverse polynomial error -- a crucial property for applications in learning since we are only allowed a polynomial number of samples. While algorithms are known for exact tensor decomposition in some overcomplete settings, our main contribution is in analyzing their stability in the framework of smoothed analysis. Our main technical contribution is to show that tensor products of perturbed vectors are linearly independent in a robust sense (i.e. the associated matrix has singular values that are at least an inverse polynomial). This key result paves the way for applying tensor methods to learning problems in the smoothed setting. In particular, we use it to obtain results for learning multi-view models and mixtures of axis-aligned Gaussians where there are many more "components" than dimensions. The assumption here is that the model is not adversarially chosen, formalized by a perturbation of model parameters. We believe this an appealing way to analyze realistic instances of learning problems, since this framework allows us to overcome many of the usual limitations of using tensor methods.Comment: 32 pages (including appendix

Non-Redundant Spectral Dimensionality Reduction

Spectral dimensionality reduction algorithms are widely used in numerous domains, including for recognition, segmentation, tracking and visualization. However, despite their popularity, these algorithms suffer from a major limitation known as the "repeated Eigen-directions" phenomenon. That is, many of the embedding coordinates they produce typically capture the same direction along the data manifold. This leads to redundant and inefficient representations that do not reveal the true intrinsic dimensionality of the data. In this paper, we propose a general method for avoiding redundancy in spectral algorithms. Our approach relies on replacing the orthogonality constraints underlying those methods by unpredictability constraints. Specifically, we require that each embedding coordinate be unpredictable (in the statistical sense) from all previous ones. We prove that these constraints necessarily prevent redundancy, and provide a simple technique to incorporate them into existing methods. As we illustrate on challenging high-dimensional scenarios, our approach produces significantly more informative and compact representations, which improve visualization and classification tasks

Reaction of benzylidenephenylsulfonylacetophenone with trimethyl phosphite and tris(dimethylamino) phosphine

1. Benzylidenephenylsulfonylacetophenone (I) reacts with trimethyl phosphite (80°, C6H6) to give 2,2,2-trimethoxy-3,5-diphenyl-4-phenylsulfonyl-1,2-oxa-4-phospholene (II). 2. Two processes take place simultaneously at high temperatures (160°): isomerization of phosphorane (II) to give the dimethyl ester of 1,3-diphenyl-2-phenylsulfonyl-3-methoxy-2-propenephosphonic acid (VI), and decomposition of phosphorane (II) to the starting reactants with a cleavage of the P-C bond. 3. When phosphorane (II) is reacted with proton-donor reagents the phosphorane ring is opened at the P-O bond to give the dimethyl ester of 1-phenyl-2-benzoyl-2-phenylsulfonylethanephosphonic acid (III). 4. Benzylidenephenylsulfonylacetophenone (I) reacts with tris(dimethylamino)phosphine to give the 1:1 adduct with a bipolar structure (VII) and containing the P-C bond. Its hydrolysis and reaction with dry HCl gas were studied. © 1973 Consultants Bureau